Lab 8 - Human & Fish Electromyography Flashcards
What is an innervation ratio?
Refers to the number of muscle cells innervated by a single motor neuron.
What is a motor unit?
The sum of all the muscle cells activated by a single motor neuron.
How would the innervation ratios compare of your fingers versus your legs?
Small muscles of the fingers require precision control and have low innervation ratios for their motor units (~1:10)
Large leg muscles require less precision control and have high innervation ratios (~1:500)
What is the degree of contraction in skeletal muscles dependant on?
The number of motor units which are activated and the frequency of motor nerve impulses.
What is the phenomenon known as tonus?
Its how even at rest, muscles have a small number of motor units that are active which maintain a small degree of activity.
What is it called to increase the activation of motor units to a muscle?
Motor unit recruitment
What is an electromyogram?
The recording of the sum of all electrical activity coming form muscle fibres in a muscle
What is electromyography?
The process of making the recording of an electromyogram.
What is electromyography used for?
To detect human medical pathologies, to study human biomechanics, to study animal physiology, etc.
What are Mauthner cells and what are they used for?
Mauthner cells are specialized neurons that activate motor neurone on the opposite side of the stimulus.
When a fish is startled, is initiated which causes the fish to bend (C-shape) and then flip its tail fin to push quickly away in the opposite direction of the stimuli.
